A joint experimental and theoretical study of kinetic and mechanism of rearrangement of allyl p-tolyl ether

A joint theoretical and experimental study of the kinetic and mechanism of the rearrangement of allyl p-tolyl ether was performed in order to study the kinetic and mechanism of the reaction. Experimental studies were performed in gas phase over a temperature range of 493.15-533.15 K. The experimental Arrhenius parameters of this reaction were measured to be E-a = 36.08 kcal mol(-1), Delta S-# = -7.88 cal mol(-1) K-1, and Log A = 11.74, experimentally. Using GC for the mixture of the reaction with and without cyclohexene demonstrated that the reaction is clean without any radical intermediates. The experimental results show that the studied reaction is unimolecular and proceeds through a concerted pathway. Theoretical calculation were performed at RHF and B3LYP levels of theory using 6-31G(center dot), 6-31++G(center dot center dot) and 6-311G(center dot) basis sets. These calculations showed that the reaction proceeds through an asynchronous concerted mechanism. The calculated kinetics parameters especially at B3LYP/6-31G(center dot) level of theory are in good agreement with the experimental data. Also polarizable continuum model was used to study solvent effect on the reaction rate. These calculations indicated that the rate enhancement of the reaction in polar and protic solvents arise from specific solute-solvent interactions such as hydrogen bonding and the hydrophobic effects of solvent. (C) 2008 Elsevier B.V. All rights reserved.